1-alkenyl s-hydrocarbylmercaptoalkyl ethers and process for the same



United States Patent Ofiiice 2,806,884 Patented Sept. 17, 1957 2,806,884l-ALKENYL S-HYDROCARBYLMERCAPTOALKYL aldehyde or ketone. The alcoholsuseful in our method of making the new unsaturated ethers may beprepared by reacting a hydroxy alkyl halide with an alkali hydro carbylmercaptide, as illustrated by:

THE QND THE WE 5 E Rs PROCESS FOR S ClAOH+NaSB- BSAOH-I-NaCI William J.Tapp Charleston and Amelia E. Montagna South Charleston, W.Vaniassignors to U i i or by reactinga hydrocarbyl halide with'analkahhydroxy Corporation, a corporation of New York alkyl apt asIllustrated by:

No Drawing. Application January 11', 1956, BCI+NaSAOH BSAOH+NaCl SerialNo. 558,429 I h d d d h B y b nt e compoun s in icate in't 'e'seequations, is a y Clalms- (CL 260 509) drocarbyl radical free ofacetylenic unsaturation, by which designation it is intended to includemonovalent' hydro- This invention relates to new sulfur-containinguns'at 15 Carbon radicals Such 35 alkyl; f y y y y urated ethers and toa process for their production. In alktfehyh afyl, afalkyl and the K Ais alkylefle particular, it relates to l-alkenylS-hydrocarbylmerc'aptotadtcal- H alkyl e h A particularly desirable pathto alcohols of the above The compositions of this invention can berepresented t Whetelh A 15 an ethylene methylethylefle b h general h i lf m l radical is via the reaction between ethylene oxide or r 1e eoxidend -n1 a R1R2C=CR3OASB P PY I1 a a erc ptan,illustrated by V wherein R1,R2, and R3 are hydrogen or alkyl radicals, A BSH 3 7 FSCHBCEOH is analkylene radical, and B is a hydrocarbyl radical free 0 of acetylenicunsaturation. OH

Compounds such as these are valuable in the formation H A 3 E ofpolymeric materials and provide new routes to useful BSH BS 110E203 anS0 12 H E compositions. The Diels-Alder reaction with such com- 0 poundsprovides a method for forming substituted cyclo hexenes, dihydropyrans,andso f rth Addition-any, The ethers ultimately derlved from suchalcohols as dro'genation of the unsaturated ethers leads to useful these111 the formhla the alcohols and i the solvents and extractants.Furthermore, polymerization forhlula the ether? 15 an ethylene amethylethylehe of these new compositions leads to materials which areTadlcal) are aqqspeclallypreferredgroup 0f ethefs [20th particularlywell suited to use as oil additives whereby the as new composltlohs and1n the method 0111 lllventlollviscosity-temperature properties of theoil are improved Table 1, followlhg, Shows the .s-suhstltuted h p andthe tendency of the lubricant toward oxidativ'e de- 311911018 have h dalong Wlth then P y P P' composition is inhibited. erties. The ethersillustrated in Table 1 were made by Our preferred method of making thenew sulfur-conreacting the appropriate hydrocarbyl halide with thetaining unsaturated others is by way of the liquid phase required alkalihydroxy alkyl mercaptide.

TABLE 1 V Molecular r'etrac- V 7 Yield Bolling Specific Refractive tionPurity, Compound percent point, gravity at inderat a. peroiuieory 0., at20/20 C. 20 0. c'eht 10 mm. Calcu- Observed lated S-substltutedMercaptoalkanols: a

S-methylmerca toethanoL- 91. 0 61 1. 0628 1.4946 25. 55 2 5. 22S-ethylmermptoe'than01 91, 2 752 1. 0177 1. 4872 30. 17 30. 05 99. 2S-allylmercaptoethanoL- 93.3 87 1.0307 1.5096 34.32 34. 22 99.5s-butylmercaptoethanolun 93.0 97 0.966 1 4800 38. as. 32S-hexylmercaptoethanol 1 77. 0 124 0. 9457 1. 4781 '48. 60 48. 99. 8S-(Z-ethylhexyDmerwp'toet 1101 88.8 136 0.9354 1. 4783 57.88 67,50 100.0S-benzylmercaptoethanol; 86. 2 157 1. 103 1. 5770 49. 66 50. 99. 1

n Determination of hydroxyl content by acylation.

dealcoholation of the corresponding acetals or ketals. As is well known,acetals and ketals may be formed via the reaction between two mol's ofan alcohol and one of an Acet'a'ls and ke'tal's suitable for theproduction of the compositions of this invention may be obtained by wayof the reaction between a hydroxy thio other and an" i catalyst ifRIRRGH O +2BSAOH RlRzCH (OASB)2+H7O In this equation R1, R2, and R3 canbe hydrogen or an alkyl radical of from 1 to 6 carbon atoms.

'Table 2, following shows the compounds of the formula R1R2CHCR3(OASB)2which we have made and the mit a lower pot temperature and thereby areduction of undesirable side reactions. Reduced pressures alsofacilitate isolation of the products.

After recovery of the crude product it may easily be refined byfractional distillation.

Other methods of refining the ethers, particularly when the majorimpurity in the ether is the corresponding S-hydrocarbylmercaptoalkanol(previously indicated by the formula HOASB), include causing the alcoholto physical properties measured. react with the ether under theinfluence of a catalyst TABLE 2 Molecular refrac- Yield Boiling pointSpecific Refractive tion Purity, Compound percent C.) at indigravity atindex at t of theory cated pressure /20 C. 20 0. cent (mm. hg) Calcu-Observed 1 lated th t th 1) 55 8 lav/10 mm 1 0612 1 4956 58 37 -me erea0e Dl(S-ethyh nercapt o ethyl) 58.4 159l10 mm 1.0216 1. 4894 67.60Di(S-a11ylmercaptoethyl) 47. 5 164l5 mm 1. 0345 1.5097 75. 91D1(S-butylmere1ptoethyl 57.0 170/3 m1n 0.9783 1. 4829 86. 08D1(S-hexylmercaptoethyl) 62.0 l97l2 mm 0. 954 1. 4805 104. 50DiIS-(Z-ethylhexyDmerca-ptoethyl] 50. 1 216l2 mm 0. 9434 1. 4807 123. 02Dl(S-benzylmercaptoethyl) 69.1 24fi/2-5 mm 1.115 1.5725 106.59

i is-methylmercaptoethyl) t. 52. 3 161l10 mm.. 1.0265 1. 4889 67. 61D1(S-buty1r nerc aptoethy1) 55. 4 196l5 m 9639 1. 4807 95. 32

8 Determination of acetal content by hydrolysis and analysis toraldehyde by reaction with hydroxylamine.

0 such as originally employed to effect the dealcoholation The course ofthe reaction by which the ether is formed is indicated by the equation:

From this equation it is seen that one of the products is the hydroxythio ether from which the acetal may be formed. This hydroxy thio ethermay advantageously be employed to make more of the acetal.

Following the general procedure given above, and appearing in greaterdetail. hereinafter, lralkenyl' S-hydrocarbylmercaptoalkyl ethers havingthe above formula wherein R1, R2 and R3 may each be a hydrogen atom oran alkyl radical such as methyl, ethyl, propyl, butyl, hexyl, and thelike; A may be alkylene radical-such as ethylene, methylethylene,propylene, butylene, and so forth, and B is a hydrocarbyl radical suchas methyl, ethyl, propyl, butyl, 2-etl1ylbutyl, hexyl, Z-ethylhexyl,octyl, lauryl, allyl', benzyl, cyclohexyl, and the like, may beprepared.

The method of our invention involves dealcoholating a compound of theformula:

- atRzoflixoasB),

in the liquid phase in the presence of a strong acid catalyst andrecovering from the reaction mixture a l-alkenylS-hydrocarbylmercaptoalkyl ether of the formula:

a R R2C=i30AsB in which R1, R2 and R3 can be hydrogen or an alkylradicaloffrom l to 6 carbon atoms; A is an alkylene radical of from 1 to 4carbon atoms; 'and B is a'hydro carbyl radical free of acetylenicunsaturation and containing from 1 to 12 carbon atoms. Our preferredmethod for recovering the e ther from the reaction mixture is bydistillation.

We have discovered that markedly improved yields of the l-alkenylS-hydrocarbylmercaptoalkyl ethers are obtained if the ether is removedfrom the reaction mixture substantially at the rate at which it isformed.

1 -A suitable apparatus for the reaction is a reaction vessel providedwith a source of heat and fitted with a fractionating distillationcolumn. For optimum results, the distillation column should be so chosenas to be of a capacity to handle the products at the rate produced.

In most cases the reaction may advantageously be conducted under reducedpressures. Reduced pressures perwith the consequent formation of anacetal and, after neutralizing the catalyst, distilling the ether toseparate it from the higher boiling acetal.

, Another method of purifying the, ethers comprises codistilling theether as a minimum boiling azeotrope from the mixture. Water-solublelower alkyl glycols form suit able minimum boiling;azeotropes.Illustrative of such glycols are ethylene glycol, diethylene glycol andpro pylene glycol. After separating the ether by means of such a minimumboiling azeotrope the glycol can be removed from the ether by'extractingthe glycol from the ether with water.

Strong acids such as sulfuric, phosphoric, the aromatic sulfonic acids,and other substantially non-volatile acids of comparable strength areall suitable catalysts. The preferred catalyst is phosphoric acid.,Catalyst concentrations of 0.005 to 5.0 percent by weight ofthereaction mixture may be employed. Preferably the catalyst is employed ina concentration of 0.05 to 1.0 percent by weight of the reactionmixture.- In the usual case, the catalyst concentration is determined bythe rate of decomposition desired.

A suitable range of temperatures is from C. to 250 C. when the pressurerange is selected in the range from 0.1 to 100 mm. of mercury, absolute.The preferred range of temperature is from C. to C. and is concurrentlyemployed with the pressure range of 0.1 to 10 mm. of mercury. In orderto facilitate rapid removal of the products from the reaction mixture,it is preferred that a reaction temperature higher than the V boilingpoint of ,the ether, at the reaction pressure, be

pound being. dealcoholated, i. e., the acetal or ketal beingdealcoholated. 4 v 7 Inasmuch as the products formed by decompositionoflthe'acetal can react to again form the acetal, particularly so underacidic conditions, it is desirable that the products he collected underalkaline conditions. A variety of alkaline materials are suitable forproviding the desired alkalinity. They include inorganic bases such assodium carbonate and hydroxide, alcoholates such as so- 'diumalcoholate, and amines such as di(2-ethylhexyl) amine andtriethanolamine.

a The use of an inert diluent in the reaction mixtur '5 is notrequisite. to the successful operation of our method; however, such adiluent may be employed.

In a preferred method of producing the ethers of our invention, areaction mixture of the corresponding acetal or ketal and asubstantially non-volatile strong acid is heated under reduced pressureto a temperature sufiicient to vaporize the-ether-; the ether isrecovered by condensing the vapor so produced, and collecting thecondensate under alkaline'conditions;

A preferred method for making; l-alkenyl S.-hydrocarbylmercaptoalkylethers of they formula s nrRro=r ioxsB wherein R1, R2 and R3 can behydrogen. or an alkyl radical of from 1 to. 6. carbon atoms and R1, R2and Rs taken. collectively contain at most carbonv atoms; A is analkylene radical of from. 1 to 4' carbon atoms; B is a hydrocarbylradical free of acetylenic unsaturation containing from 1 to 12 carbon.atoms; and. R1, R2,. R A, and B taken collectively contain, at most, '20carbon atoms, comprises heating areactionmixture of the correspondingcompound of the formula nlRroHc x'o'asBh and a strong acid catalystwhich is substantially nonvolatile under the reaction conditions in theliquid phase to a temperature sufficient to vaporize the l-alkenyl S-hydrocarbylmercaptoalkyl ether and an alcohol co-product of the formulaHOASB, thereby dealcoholating the said heated compound and forming andvaporizing said ether and. said alcohol. co-product and recovering thevapors of the ether and the alcohol. co-product.

When the hydrocarbyl radical, B, is ethylenically unsaturated improvedyields are obtained if the above-described process is modified by firstheating the compound being dealcoholated to. a temperature atwhich theether produced is. vaporized and thereafter initiating thedealcoholation reaction by adding. the acid catalyst. By adding thecatalyst after the acetal or ketal' has been brought to the desiredoperating temperature the formation of polymeric by-products isrepressed and the yield of ether is improved.

By the method ofv our invention, we have made the compositions of ourinvention, the l-alkenyl' S-hydrocarbylmercaptoalkyl. ethers of theformula:

s. RrR2C= O'ASB.

wherein R1, R2 and R3 can be hydrogen or an alkyl radical of from 1 to 6carbon atoms and R1, R2 and Ra taken collectively contain at most 10carbon atoms;-A is an alkylene radical of from: 1 to 4 carbon atoms; Bis a hydrocarbyl radical free of acetylenic unsaturation containing from1 to 12 carbon atoms; R1, R2, R3, A, and B taken collectively contain atmost- 20' carbon atoms;

These ethers are colorless compounds having the marked odorcharacteristic of compounds containing a thioether group, They show thechemical characteristics of 1- alkenyl ethers in that they react withalcohols to form acetals and maybe hydrolyzed to form aldehydes andalcohols.

The following examples are illustrative:

Example I;Vinyl 'S-methylmercaptoethyl ether (A) PREPARATION OFS-HETHYLMERCABTO- ETHANOL 6 continuously and vigorously stirred.Thestirring wasv continued thereafter until all of the solid sodiumhydroxide had been dissolved. The heat of reaction evolved from theformation of the mercaptide was sufficient to cause the ethanol toreflux in the brine-cooled condenser. After all of the sodium hydroxidehad entered into solution, the addition funnel was replaced by aconvenient length of 6-mm. glass tubing one end of which extended wellbelow the surface of the liquid mixture. Through this tube, 1263 grams(25 moles) of methyl chloride gas were added while the reaction mixturewas vigorously stirred. Because this reaction was exothermic no externalheating was necessary during the initial three hours' of the feedingperiod. The rate of feed was determined by the cooling capacity of thereflux condenser. A total period of five hours was required to completethe addition of. methyl chloride. The reaction mixture was stirred foran additional period of two hours at total reflux. Then, after thereaction mixture had cooled to room temperature, it was filtered througha Buchner funnel and the precipitate of sodium chloride was washed with2 liters of ethanol. The combined filtrate and washings were distilledthrough a 25 by 600-mm. still column packed with stainless steelsaddles. After essentially all of the ethanol had been distilled atatmospheric pressure, and after a small forerun at reduced pressure, afraction distilling at C. at 22 mm. of mercury pressure was collected.This distillate, S-methylmercaptoethanol amounted to 2091 grams (22.7moles) which corresponded to a yield of 91 percent of the theoreticalvalue.

(B) PREPARATION OF DI(S-METHYI2MERCAPTO- ETHYL)ACETAL To a 5-literreaction flask equipped with stirrer, addition funnel, reflux condenser,and thermometer, was charged 3312 grams (36 moles) ofSmethylmercaptoethanol and 1.9 grams of concentrated sulfuric acidcatalyst. To this mixture was added 528' grams (12 moles) ofacetaldehyde during a period of 5 minutes during which period thetemperature of the reaction mixture increased from 25 C. to 52 C. Afterthe maximum temperature, 52 C., was reached the mixture was stirred forone hour. Following this period, 55 grams of a 10 percent aqueoussolution of potassium hydroxide was added and stirring was continued foran additional period of one hour. The crude product was distilled atreduced pressure using a 25 by GOO-mm. column packed with 6- mm. glassrings. After removing the low-boiling materials, such as acetaldehyde,water, etc., unreacted S- methylmercaptoethanol amounting to 22.2 moleswas recovered. A fraction, 1408 grams (6.69 moles) ofdi-(S-methylmercaptoethyl)acetal, boiling at from 98 to C. at 1 mm. of mercuryabsolute pressure, was collected; This corresponded to a yield of 55.8percent of theory, based upon the quantity of acetaldehyde'charged;

(O) PREPARATION OF VINYL S-METHYLMERCAPTO- ETHYL ETHER Into aSOD-milliliter flask equipped with an addition funnel and a thermometer,and attached to a 25 by 300 mm. still column packed with stainless steelsponge and fitted with a total-condensing variable takeoff still head;there was placed 200 grams of di-(S-methylmercaptoethyl)acetal and 1.0ml. of 85 percent phosphoric acid catalyst. To prevent recombination ofthe co-pr-oducts, vinyl S-methylmercaptoethyl ether andS-methylmercaptoethanol, 3.0 ml. of triethanolamine was placed into theproduct receiver. The pressure in the system was reduced to from 3 to 5mm. of mercury, and the mixture was heated at a reaction temperature offrom -to C. The crude product was distilled at a reflux ratio of about1:1 at a vapor temperature of from 55 to 70 C. Additional acetal was fedto the reaction flask to replace the amount decomposed. A total of 900grams (4.28 moles) of acetal was dealcoholated in the reaction. and thecrude product upon redistillation yielded. 5G0

. 7 grams of an azeotropic mixture, 80 percent of which was vinylS-methylmercaptoethyl ether and percent was S-me thylme rcaptoethanol'.The yield of ether corresponded to'79.0 percent of the theoreticalyield.

Refined ether was prepared by treating a portion of the azeotrope with afew drops of a percent solution of sulfuric acid inS-methylmercaptoethanol. An exothermic reaction occurred in which thealcohol present was reconverted to the acetal by reaction with some ofthe vinyl ether. Following neutralization of the acid, the reactionmixture was fractionally distilled to yield a product with the followingproperties: B. P.=43 C. at 10 mm. Hg, 63 C. at mm. Hg, and 74 C. at mm.Hg; n =l.4774; sp. g. at 20/20 C.=0.9739; molecular refraction,calculated=34.44, observed=34.3l; and purity=97.3 percent bydetermination or" the vinyl ether function.

7 Example II.Vinyl S-ethylmercaptoethyl ether (A) PREPARATION'OFS-ETHYLMERCAPTOETHANOL Di (S-ethylmercaptoethyl)acetal was prepared fromacetaldehyde and S-ethylmercaptoethanol by a procedure similar to thatin Example I, and the product, B. P. 126-l30 C. at 1.5-2 mm. of mercuryabsolute pressure,

was isolated in a yield of 58.4 percent of theory, based 1 uponacetaldehyde charged to the reaction mixture.

(C) PREPARATION OF VINYL S-ETHYLMERCAPTO- ETHYL ETHER Dealcoholation ofthe acetal by the procedure described in Example I produced vinylS-ethylmercaptoethyl ether in 71.3 percent yield based upon ethercontained in the azeotropic mixture. Refined vinyl ether was prepared as7 described in Example I, and exhibited the following properties: B. P.at 10 mm. of Hg= C.; specific gravity 20/20 C.=0.9509; refractive index,115 214738; molar refraction, calculated=39.05, observed=39.00; purity:98.5 percent.

.Example III.Vinyl S-allylmercaptoethyl ether S-allylmercaptoethanol anddi(S-allylmercaptoethyl)- acetal were prepared from allyl chloride,mercaptoethanol, and acetaldehyde, by procedures similar to thosedescribed in Example I, in yields of 93.3 and 47.5 percent of theoryrespectively. Dealcoholation of the acetal gave vinylS-allylmercaptoethyl ether in 65.5 percent yield based upon the vinylether content of the azeotropic mixture. Refined ether was prepared bythe same process as described in Example 1 and exhibited the followingproperties: B. P. at 15 mm. of Hg=78 C.; specific gravity of 20/20 O-0.9666; refractive index n =l.4920; molecular refraction,calculated:43.21, observed=42.85; purity97 .2 percent.

Example 1V.Vinyl S-butylmercaptoethyl ether S-butylmercaptoethanol anddi(S-butylmercaptoethyl)- acetal were prepared from butyl chloride,mercaptoethanol, and acetaldehyde, by procedures similar to thosedescribed in Example I, in yields of 93.0 and 57.0 percent of theoryrespectively. Dealcoholation of the acetal gave vinylS-butylmercaptoethyl ether in 84.7 percent yield based upon the vinylether content of the azeotropic mixture. Refined ether was prepared bythe process described in Example I and exhibited the following properties: B. P. at 10 mm. of Hg=87 C.; specific gravity 20/ 20 C.=0.9268;refractive index n =l.4710; molecaspires;

ular refraction, calculated=48.29,

pun'ty=99.l percent. 7 V

1 Example V.-Vinyl S-Hexylmercaptoethyl ether S-Hexylmercaptoethanol anddi (S hexylmercaptoethyl)acetal were prepared from hexyl chloride,mercaptoethanol, and acetaldehyde, by procedures similar to-observed=48.60;

those "described in Example I, in yields of 77.0 and 62.0 7

percent respectively. Dealcoholation of the acetal gave vinylS-hexylmercaptoethyl ether in a yield of 89.5 percent based upon theether content of the azeotropic mixture. Refined ether was obtained bycodistillation of this azeotropic mixture with ethylene glycol to yieldan etherethylene glycol azeotrope from which the glycol was removed byextraction using water. Further refining was accomplished as describedin Example I; the ether then exhibited the following properties: B. P.at 10 mm. of Hg=115 C.; specific gravity 20/20 C.=0.9l28; refractiveindex n =1.4707; molecular refraction, calculated=58.53, observed=57.60;purity=98.4 percent.

S-(Z-ethylhexyl) mercaptoethyl ether S-(Z-ethylhexyl)mercaptoethanol anddi-[S-(Z-ethylhexyl)rnercaptoethyl] acetal were prepared fromZ-ethylhexyl chloride, mercaptoethanol, and acetaldehyde, by proceduressimilar to those described in Example I, in yields of 88.8 and 50.1percent respectively. Dealcoholation of the acetal gave vinylS-(2ethylhexyl)mercaptov Example VI.-Vinyl ethyl ether in 75.9 percentyield based upon the ether content of the azeotropic mixture. Refinedether was obtained by codistillation with diethylene glycol as describedin Example V, and exhibited the following properties: B. P. at 10 mm. ofHg=132 C.; specific gravity 20/20 C.=0.9079; n =l.4717; molecularrefraction, calculated=66.76, observed=66.50; purity=98.5 percent.

Example VII.Vinyl S-benzylmercaptoethyl ether S-Benzylrnercaptoethanoland di(S-benzylmercaptoethyl) acetal were prepared from benzyl chloride,mercaptoethanol, and acetaldehyde, by methods similar to those describedin'Example I, in yields of 86.2 and 59.1 7

percent, respectively. Dealcoholation of the acetal gave vinylS-benzylmercaptoethyl ether in 72.2 percent yield,

based upon the ether content of the azeotropic mixture.

Refined ether was obtained by codistillation with diethylene glycol, asdescribed in Example V. Properties of the refined ether are as follows:B. P. at 1 mm. of Hg= C.; specific gravity 20/ 20 C.==l.053; refractiveindex n =1.5500; molecular refraction, calculated=58.54, observed=58.75;purity=l00.0 percent.

Example VIII.1-butenyl S-methylmercaptoethyl etherDi-(S-methylmercaptoethyl)butyral was prepared from the reaction ofS-methylmercaptoethanol and n-butyral- Example IX.I-butenyl S-butylmercaptoethyl ether Di-(S-butylmercaptoethyl)butyral was preparedfrom S-butylmercaptoethanol and butyraldehyde, as in Example VIII in55.4 percent yieldf Dealcoholation and refining, as in Example 8, gavel-butenyl S-butylmercapwherein R and R3 are H and R1 is selected fromthe group consisting of H and alkyl radicals of from 1 to 6 carbonatoms; A is an alkylene radical of from 1 to 4 carbon atoms; B isselected from the group consisting of alkyl radicals of from 1 to 12carbon atoms, benzyl radical, and allyl radical: R1, R2, R3, A, and Btaken collectively contain at most 20 carbon atoms.

2. The compositions of claim 1 wherein R1, R2 and R2 are H.

3. The compositions of claim 1 wherein R1 is an ethyl radical and R2 andR3 are H.

4. The compositions of claim 1 wherein R1, R2, and R are H, and A is anethylene radical.

5. The compositions of claim 1 wherein R1 is an ethyl radical, R2 and R3are H, and A is an ethylene radical.

6. Vinyl S-ethylmercaptoethyl ether.

7. Vinyl S-(Z-ethylhexyl)mercaptoethyl ether.

8. Vinyl S-benzylmercaptoethyl ether.

9. Vinyl S-allylmercaptoethyl ether.

10. l-butenyl S-butylmercaptoethyl ether.

11. The method of making a l-alkenyl S-hydrocarbylmercaptoalkyl ether ofthe formula wherein R2 and R3 are H and R1 is selected from the groupconsisting of H and alkyl radicals of from 1 to 6 carbon atoms, A is analkylene radical from 1 to 4 carbon atoms, and B is selected from thegroup consisting of alkyl radicals containing from 1 to 12 carbon atoms,benzyl radical, and allyl radical which comprises heating a reactionmixture of the corresponding compound having the formula s RIR CHewASBMand a strong acid catalyst selected from the group consisting ofphosphoric acid, sulfuric acid, and aromatic sulfonic acids, in theliquid phase to a temperature sufficient to vaporize the said l-alkenylS-hydrocarbylmercaptoalkyl ether and the alcohol co-product of theformula HOASB thereby dealcoholating said compound and forming andvaporizing said ether and said alcohol coproduct; and recovering saidvapors.

12. The method of making a l-alkenyl S-hydrocarbylmcrcaptoalkyl ether ofthe formula wherein R2 and R3 are H and R1 is selected from the groupconsisting of H and alkyl radicals of from 1 to 6 carbon atoms, A is analkylene radical from 1 to 4 carbon atoms, and B is selected from thegroup consisting of alkyl radicals containing from 1 to 12 carbon atoms,benzyl radical, and allyl radical which comprises heating a reactionmixture of the corresponding compound having the formula a RrRzCH?(CASE):

and a strong acid catalyst selected from the group consisting ofphosphoric acid, sulfuric acid, and aromatic sulfonic acids, in theliquid phase to a temperature near the boiling point of the compoundheated under a reaction pressure in the range from 0.1 mm. to mm. ofmercury absolute, thereby forming and vaporizing said ether and analcohol co-product of the formula HOASB, and recovering said vapors.

13. The method of making a l-alkenyl S-hydrocarbylmercaptoalkyl ether ofthe formula wherein R2 and Rs are H and R1 is selected from the groupconsisting of H and alkyl radicals of from 1 to 6 carbon atoms, A is analkylene radical from 1 to 4 carbon atoms, and B is selected from thegroup consisting of alkyl radicals containing 1 to 12 carbon atoms,benzyl radical, and allyl radical which comprises heating a reactionmiXture of the corresponding compound having the formula and a strongacid catalyst selected from the group consisting of phosphoric acid,sulfuric acid, and aromatic sulfonic acids in the liquid phase to atemperature in the range of from 100 C. to 250 C. and under a pressurein the range of from 0.1 to 100 mm. of mercury, said temperature beingsuflicient to vaporize said ether and an alcohol co-product of theformula HOASB thereby dealcoholating said compound and forming andvaporizing said ether and said alcohol co-product.

14. The method of making a l-alkenyl S-hydrocarbylmercaptoalkyl ether ofthe formula wherein R2 and R3 are H and R1 is selected from the groupconsisting of H and alkyl radicals of from 1 to 6 carbon atoms, A is analkylene radical of from 1 to 4 carbon atoms and B is selected from thegroup consisting of alkyl radicals containing from 1 to 12 carbon atoms,benzyl radical, and allyl radical, and wherein R1, R2, R3, A, and Btaken collectively contain at most 20 carbon atoms, which comprisesheating a reaction mixture of the corresponding compound having theformula and a strong acid catalyst selected from the group consisting ofphosphoric acid, sulfuric acid, and aromatic sulfonic acids, saidcatalyst being present in an amount of from 0.005 to 5.0 percent byweight of the reaction medium, in the liquid phase to a temperature inthe range from 100 C. to 250 C. and under a pressure in the range offrom 0.1 to 100 mm. of mercury, said temperature being greater than theboiling point of said ether under the reaction pressure, therebydealcoholating said compound and forming and vaporizing said ether andan alcohol co-product of the formula HOASB, and condensing andrecovering said vapors.

15. The process of claim 14 wherein the strong acid catalyst isphosphoric acid.

OTHER REFERENCES Hill: I. Am. Chem. Soc. 50, 2725-2731 (1928).

1. THE 1-ALKENYL S-HYDROCARBYLMERCAPTOALKYL ETHERS HAVING THE FORMULA:11. THE METHOD OF MAKING A 1-ALKENYL S-HYDROCARBYLMERCAPTOALKYL ETHER OFTHE FORMULA